Process of metal coating



Patented Apr. 2, 1

ore-ice raocsss 0F METAL coa'rma Joseph K. Schoileld, West nil-mm, Conn.

No Drawing. Application May 25, 1937, Serial No. 144,665

' 14 Claims. (01. 204-13) This invention relates to coating metals such as iron and steel by plating with copper and also with another metal having a higher fusing point and preferably being also materially harder and more resistant to abrasion than copper.

An object of the present invention is to plate metals such as iron and steel preliminarily with one metal preferably by electro-plating, then plate the same surface with another metal and finally after the second plating operation, heat the plated 'metal sufficiently high to fuse one of the plated coatings so that it will closely adhere layer of copper.

to the base metal and intimately mingle with the metal particles of the other plated metal.

One feature that enables the above object to be attained is that the plated metal fused by the heating is copper and that the fusing preferably takes place in a heated hydrogen atmosphere or in an atmosphere substantially free from oxygen.

In carrying out the above described process the article to be coated is first plated with a thin This plating may preferably be done by electroplating in the usual manner in a standard plating bath. The thickness of the plate need not be very great but sumcient deposit should be made so that upon fusion of the copper during the subsequent heating operation there shall be enough to fuse with the metal forming the second plated metal and form an intimate bond between the base metal and the second .plated metal over their entire surface. 1

If desired the relative amounts of copper and of the second plated metal, usually chromium, may be such that all of the copper may be alloyed with the second plated metal, there preferably being free chromium or other second plated metal on the exposed surface.

The second plated metal may preferably be chromium which has a higher melting point than copper and is of much greater hardness. Any other metal, however, such as nickel, that has a higher melting point than copper and can be plated upon copper may be used.

After the base metal, iron or steel, has been plated with copper and another metal such as chromium in the manner above-described, the plated article is then heated in a non-oxidizing atmosphere to a temperature approximating that for fusing the copper. The article is held long enough at that temperature to melt the copper and permit it to form a dense homogeneous but thin and compact layer over the base metal entirely free from minute openings. The copper during this step of the process intermingles with and fills in'any minute openings in the chromium thereafter plating the article with a flash plate or other plated material overlaying the copper I which render chromium plated surfaces porous.

After heating as above described has taken place and the copper has been fused sufiiciently to fiow over the. surface of the base metal and 5 form a complete bond or alloy with the chromium adjacent their contiguous surfaces the article is allowed to cool. Finally, if desired, the plated surface of the article may be given a third plating' operation to completely plate the surface with 10 chromium or other material and to conceal any traces of copper that may appear through the earlier ap lied second plate. After this final plating operation has taken place the surface may be buffed or otherwise finished to give the surface 1 effect desired. A polished or bright finish to the article may be obtained by polishing the article where necessary, after the heating in the non-oxidizing heated atmosphere such as hydrogen and of chromium.

I claim:

1. A process of coating metal comprising electro-plating said metal with copper and chromium, and thereafter maintaining said plated metal for a short period at the melting temperature of copper.

2. A process of coating metal comprising electro-plating said metal with copper and chromium, and thereafter maintaining said plated metal in a hydrogen atmosphere for a short period at the melting temperature of copper.

3. A process of coating metal comprising electro-plating said metal first with copper and then with a metal having a higher fusion point than copper, and thereafter maintaining said plated metal in a hydrogen atmosphere for a short period at the melting temperature of copper. v

4. A process of coating metal comprising separately depositing platings thereon of copper and 40 i plated metal in a hydrogen atmosphere to the melting temperature of copper. g.

"I. A process of coating iron msteel comprising plating said metal with a layer 0! copper, then plating said copper plated metal with a layer of a metal having a higher fusion point than copper and having greater hardness, thereafter heating said double plated metal to stemperature sumcient to cause melting of said cop per, and allowing said metal to cool slowly.

8. A process of coating iron or steel comprising electro-plating said metal with a layer of copper. then electro-plating said copper plated metal with a layer of chromium, thereafter heating said double'plated metal to a temperature sufficient to cause melting of said copper, and allowing said metal to cool slowly.

9. A process of coating iron or steel comprising electro-plating said metal with a layer of copper, then electro-plating said copper plated metal with a layer of chromium, and thereafter heating said double plated metal in a hydrogen atmosphere to a temperature suflicient to cause melting of said copper and allowing said metal to cool slowly. I 4

10. A process of coating iron or steel comprisingv first electro-platingsaid metal "with a layer of copper, then electro-plating said copper plated metal with a layer of a metal having a higher fusion point than copper and having greater hardness, and thereafter heating said.

double plated metal in a hydrogen atmosphere arcane said copper, and finally allowing said metal to I ing plating said metal with a layer of copper,

then plating said copper plated metal with a layer of a metal having a higher fusion point than copper and having greater hardness, thereafter heating said double plated metal to a temperature suflicient to cause melting of said copper in'a non-oxidizing atmosphere, and allowing said metal to cool slowly.

l4=.' A process of coating iron or steel comprising electro-plating said metal with 'a layer of copper, then electroj-plating said copper plated metal with a layer of chromium, thereafter heating said double plated metal to a temperature. suilicient to cause melting of said copper in a non-oxidizing atmosphere, 'and allowing said j metal to cool slowly. to atemperature sufllcient to cause melting of j JOSEPH 'x. scnor'mm. 

